Improvement of Corn Yield and Sensor Reading Relationship with Consideration of Crop Height.

Corn was grown in a nitrogen rate study with six N rates and four replications. Two active-optical sensors, the Greenseeker (TM) and Holland Crop Circle (TM) were used to collect imagery readings of the plants in each plot at both the 6-leaf stage and again about 2 weeks later. Corn grain was harvested and the grain yield was compared to sensor measurements at each date to construct and algorithm of in-season estimate of yield (INSEY). On the same dates as imagery was collected, a corn height measurement was recorded using a tape measure. Multiplying the sensor reading and the corn height measurement together usually resulted in a stronger relationship with yield and a better INSEY estimate than sensor reading alone.